A topological isomer of ferrocene: Theoretical approach for transition metal complexes with conjugated all trans cyclodecapentaene

We demonstrate the ability of all-trans DPEN as a suitable ligand for transition metals by DFT computation [B3LYP/6-311+G(2d,p) and BP86 level]. The iron complex Fe(DPEN) is a unique topological isomer of ferrocene.     

2-羟丙基-β-环糊精与二茂铁衍生物超分子胶束通过氧化还原响应控制药物释放

合成了新型的具有长链的二茂铁衍生物(P-Fc),并将其包络在2-羟丙基-β-环糊精(HP-β-CD)的空腔中,自组装形成超分子囊泡,并通过FTIR、1 HNMR、SEM和CV曲线对其进行结构形貌表征;分别以罗丹明6G(R6G)、盐酸阿霉素(DOX)作为药物,实现了R6G、DOX在囊泡中的成功装载。并通过加入氧化剂,将二茂铁氧化成二茂铁盐,将囊泡破坏,实现了 R6G 和 DOX 的快速定向释放,其药物装载量分别为6.89和39.06μg/mg,最大释放率分别为73.7%和88.2%。     

Radial tetra(ferrocenyl)- and tetra(cymantrenyl)cyclobutadienecobalt complexes: Synthesis and structures

Novel radial tetra(ferrocenyl)- and tetra(cymantrenyl)cyclobutadienecobalt complexes were prepared by metal carbonyls free protocol of [2 + 2] cycloaddition reaction of 1,2-diferrocenyl- or 1,2-dicymantrenylethynes with chlorotris(triphenylphospine)cobalt(I) and carboethoxycyclopentadienide sodium with good yields. The molecular structure of these products was confirmed with X-ray analysis, and their electrochemical behavior was studied.     

Synthesis, electrochemistry and metal binding properties of monosubstituted ferrocenoyl peptides with thioether-containing sidechains

Ferrocenoyl peptides incorporating thioether functionality respond more strongly to mercury(II) than to other heavy metal ions in solution. Compounds reported previously in this context are all 1,1′-disubstituted, and all include two or more sulfur-containing amino acids. To test whether two thioether groups are required for effective mercury binding by these systems, we have prepared a series of singly-substituted ferrocenoyl peptides from ferrocenecarboxylic acid and l-methionine, S-methyl-l-cysteine or S-trityl-l-cysteine, and tested them as electrochemical probes for mercury(II). Nine ferrocenoyl peptides have been synthesised using a Boc-protecting group strategy and HBTU-mediated peptide coupling. The electrochemical properties of these compounds have been determined using cyclic voltammetry, and all show fully reversible one electron oxidation steps. Forward sweep half wave peaks (E_F), reverse sweep half wave peaks (E_R), peak separations (ΔE_P) and half wave potentials (E_1/2) are reported. Changes in the potential of the iron(II)/iron(III) redox couple of the ferrocene core have been used to quantify heavy metal-peptide interactions, revealing that these monotopic systems also respond more strongly to mercury(II) than to zinc(II), cadmium(II), silver(I) and lead(II). NMR experiments to characterise the peptide-mercury interaction implicate the thioether sulfur as the site of mercury binding and indicate 1:1 stoichiometry. The crystal structure of ferrocenoyl-S-methyl-l-cysteine methyl ester is also reported. The greater responsiveness of these systems to mercury(II) makes them interesting leads for the development of biologically inspired sensors for this toxic heavy metal.     

Dimerisation and reactivity of HCCCCFc at ruthenium centres

In contrast to the simple diynyl complexes formed in reactions between HCCCCFc and MCl(dppe)Cp∗; (M = Fe, Ru), an analogous reaction with RuCl(PPh₃)₂Cp∗; in the presence of KPF₆ and dbu resulted in dimerisation of the diyne at the Ru centre to afford a mixture of [Ru{η¹,η²-C(CCFc)C(L)CHCCCHFc}(PPh₃)Cp∗]PF₆ (L = dbu 1, PPh₃2). Similar reactions with RuCl(PR₃)₂L gave [Ru{η¹,η²-C(CCFc)C(dbu)CHCCCHFc}(PR₃)L]PF₆ (L = Cp, R = Ph 3, m-tol 4; L = η⁵-C₉H₇, R = Ph 5). The reaction between 3 and I₂, followed by crystallization of the paramagnetic product from MeOH, afforded the dicationic [Ru{C(CCFc)C(dbu)CHC(OMe)C(OMe)CHFc}(PPh₃)Cp](I₃)₂6. The molecular structures of 2·2CH₂Cl₂ and 6.S (S = 2CH₂Cl₂, C₆H₆) were determined by single-crystal XRD studies.     

Hydrogen-bonding interactions in ferrocene-peptide conjugates containing valine

The synthesis and characterization of a series of ferrocene (Fc) peptide conjugates containing the amino acid valine is reported, where the peptide substituents are part of the hydrophobic sequence of the amyloid β-peptide. The hydrogen-bonding (H-bonding) interaction in these compounds is studied by variable temperature ¹H NMR spectroscopy. The solid-state structures, determined by single crystal X-ray crystallography, of two of the conjugates (Fc[CO-Leu-Val-OMe]₂1 and Fc[CO-Gly-Val-OH]₂6) are reported. Both structures are stabilized by intramolecular H-bonds exhibiting the familiar “Herrick motif” involving the proximal amide NH and the amide CO of the adjacent amino acid. This motif is sufficiently rigid and is maintained in solution as suggested by CD studies. However, the intermolecular H-bonding patterns observed on conjugates 1 and 6 are significantly different resulting in very different supramolecular architectures. For conjugate 1, a more conventional set of head-to-tail stacking interactions which is stabilized by β-sheet-like H-bonding interactions between the individual molecules is observed. However, for conjugate 6, the presence of the C-terminal acid group and presumably the flexibility of the Gly linker enables the formation of a more open structure that contains hydrophobic channels occupied by solvent molecules.     

Coordination chemistry of perhalogenated cyclopentadienes and alkynes. XXVIII new high-yield synthesis of monobromoferrocene and simplified procedure for the synthesis of pentabromoferrocene. Molecular structures of 1,2,3-tribromoferrocene and 1,2,3,4,5-pentabromoferrocene

Monobromoferrocene (1) was obtained in 95% yield from ferrocene via lithiation with tert-BuLi/KO-tert-Bu and bromination with dibromotetrachloroethane. Starting from 1 mixtures of 1,2-dibromoferrocene (2) and apparently unreacted 1 (ranging from 80:20 to 50:50, depending on the reaction conditions) can be obtained via a lithiation- zincation- bromination sequence. These mixtures can be transferred directly with a tenfold excess of Lithium-tetramethylpiperidinide, followed by bromination with 1,1,2,2-tetrabromoethane to pentabromoferrocene (3), in an overall yield of 36% starting from ferrocene. The molecular structures of 3 and of 1,2,3-tribromoferrocene (4) have been determined by X-Ray diffraction.     

Some aspects of organosilicon and ferrocene chemistry

This review deals with three topics selected from my researches carried out over a period of nearly 40 years up to my retirement in 1983, namely (1) methylpolysilane chemistry, (2) some chemical properties of ferrocene-substituted silicon compounds and (3) some organic syntheses catalyzed by ferrocenylphosphine-transition metal complexes.     

Computer Modelling of the Light Propagation through the Complex Anisotropy Systems - the way of a Determination of the Optical Parameters of the Liquid Crystal Displays

A mathematical and numerical method for an analysis of a liquid crystal displays (LCD) has been presented. The assumptions of the calculations of a light propagation through the display are shown. The real conditions of a work of these displays have been taken into account. Basing of this mathematical model a computer program for a numerical modelling of the optical parameters of LC displays working in real conditions has been worked out. This program makes possible to obtain the most important parameters of a display such as: contrast ratio, luminance in on- and off-state, spectral characteristics of light and its colour coordinates in these both states. The results obtained from this program have been verified experimentally. Very high conformity of these results has been obtained.